The present invention relates to a suspension fork for a bicycle and a damper system for such a suspension fork.
Employing suspension forks in bicycles has basically been known for a long time. Suspension forks configured in particular as telescopic suspension forks are installed in downhill and mountain bikes and cross-country bikes, and increasingly in everyday bicycles as well.
Most suspension forks comprise a pair of tubes stationary relative to the bicycle frame, the so-called stanchion tubes, and two lower, movable tubes, the so-called slider tubes, to which the wheel hub is fastened. The stanchion tubes may be held together by means of a fork bridge or fork crown at the center of which the fork column is attached as a rule. Most slider tubes or outer tubes are larger in diameter so as to accommodate the stationary tubes to be slidingly displaceable in the slider tubes.
The riders of suspension fork-equipped bicycles desire suspension forks whose springing and damping characteristics can be easily and quickly adjusted to speedily adapt the current suspension fork characteristics to actual ambient conditions.
Therefore, suspension forks have become known in the prior art which are provided with adjusting elements. For example U.S. Pat. No. 6,592,136 B2 discloses a suspension fork having an oil chamber provided in a lower region of a slider tube and divided into two sections by way of a movable piston. The piston rod connected with the piston is attached to the top end of the stanchion tube and configured hollow to allow an adjusting mechanism to pass through to the piston. This is a complex structure, requiring very long, thin components to adjust the damping and controls of the damper system.
Another drawback of this structure is that in operation, considerable heat is generated at the damper valve for adjusting the rebound damping and at the damper valve for adjusting the compression damping which heat spreads in the slider tube by way of the heated oil, accumulating in the lower region. Furthermore, in this known prior art the rebound stage damper valve is disposed in the lower region of the slider tube such that the heat generated in the rebound stage during damping accumulates in the lower region of the slider tube. Compression stage damper valves tend to be provided at the lowermost end of a slider tube such that the heat it generates again accumulates at the bottom.
By way of the heated oil accumulating in the lower slider tube regions where the rebound stage damper valve is provided as well, the generated heat is emitted in the lower slider tube region so as to result in the slider tube heating up more than does the stanchion tube. In this way, different thermal expansions of the slider tubes and the stanchion tubes may result.
Against the background of the described prior art it is therefore the object of the present invention to provide a suspension fork allowing a simpler structure. It is a preferred aspect of the object to provide a suspension fork comprising improved heat dissipating options.